Do you need a better solution to a problem to criticise obvious flaws in someone else's solution?

Sometimes. Depends on context. If the flaws make a solution unworkable, then they're worth bringing up. If you support the concept but would also like the flaws to be worked on, then it's worth tactfully bringing up. If no solution other than absolute perfection will satisfy you, shut the fuck up.

There's a lot of idiots and bad actors sabotaging good solutions because they want perfect solutions, and then we end up getting no solutions. So yeah. Don't do that.

I don't have to be professional chef to know that the food is bad.

Generally, no, but context and approach matter.

The ability to notice a flaw isn't the same as the skill, experience, and background that might be necessary to design a useful solution for a particular issue, especially complex issues. It's generally reasonable to say, "I don't know of a better solution, but I can predict that x and y problems will likely result from your proposed solution."

It's especially valid to warn someone when their proposed solution will harm people or make things worse. You don't have to have a better solution to try to prevent someone from doing something ill-conceived or hasty or reckless.

If the stakes are low or the person proposing a solution is likely to be sensitive to criticism, it might work better to try to approach your response as an attempt to help them refine their solution, rather than just opposing it outright. Be considerate of their feelings and make it clear you're working together.

No. Criticism is a very important thing but needs to be delivered positively to be heard. Lots of people don't have better solutions but can always help improve what's currently on the table.

Only if you’re in a stupid ego-based culture.

If you actually want to get shit done, you need to be able to criticize ideas regardless of whether you have a better idea.

Depends how invested you are in the mission. If you're actively participating helping achieve a shared goal, constructive feedback is helpful.

If something's working, but suboptimally, you can provide feedback, but don't argue with people about architecture if it's working for them.

If you want to generally be polite to your friends, or people around you, don't they say what they're doing, try to find a way to improve whatever they're doing and show a solution, or show willing to help. If you're invested people love cooperation. But if you find yourself constantly giving negative feedback to those around you, you may want to stop. It might be affecting your personal relationships.

you need to at least be able to explain what is wrong. a "this is bad" criticism is just frustrating

If the problem must be solved, and the option to do nothing isn't acceptable, then yes. Unless you're pointing them out to help mitigate them, with the acknowledgement that you will accept them regardless.

I don't need to know how to repair a helicopter, to know I'm not going to get on one that has a broken rotor.

So no, you don't need expertise or a solution to be able to identify obvious flaws.

Depends on the situation, but IMHO you need to at least be willing to accept some responsibility in improving it, and it should affect how you deliver the criticism. (Even more kindly than usual.)

If you're in a position to criticise a finished solution proposal, you're probably part of the team and could have offered your input earlier, when it was potentially even requested. Maybe they knowingly took a shortcut to be able to move on to the other tasks and meet deadlines. Maybe they took on the task outside their core skillset because someone else dropped the ball. Maybe they have banged their head against it for days and simply cannot find a solution that works on all levels, already frustrated. Is there a superior or colleague they could have asked for assistance? Are you the superior?

I think a big factor here is the size of the group you're working with. If you're frequently shooting down others and contributing no constructive alternatives in a working group of, say, 5 or fewer people... people are gonna get tired of your shit really quickly.

Feedback as part of a larger scale effort can always be useful, though.

I don't think you need a solution to point out a flaw; though I can't think of any examples where one would notice a flaw without having some kind of input on how to get around said flaw.

The German constitution has an interesting clause by which MPs may not launch a vote of confidence in the government unless they have an alternative government line-up which is ready to take over. Apparently it has some role in the legendary stability of German politics.

I think it's fine as long as you can explain what the issue is. I have meetings regularly where we are working out processes for how to handle different situations or improve on existing ones we've identified issues with. Sometimes someone will suggest something and someone else will see a gap in it and have to bring up "okay but what about if this happens" we may or may not have a solution on the spot but it identifies an issue that needs to be resolved.

On the other hand I have people who will come to me with shit like "x isn't working" which isn't helpful in resolving the problem at all. You have to be constructive about it. ex- "when I do in x, y happens"

Criticise, yes. Constructive feedback no.

When you criticise without a solution you sound like a person who doesn't know what they are talking about.

Don't do X.
Ok, why?
Because it is bad.
..... But how is it bad?

Where as constructive feedback offers alternative paths to achieve the same goal.

Don't do X, it is more faster/efficient to do Y in order to achieve your goal.

No.

It takes a lot of trial and error to articulate in a manner that does not make you seem like a dick.

Tone, environment, person, and all that needs to be taken into account before saying it.

If in good faith... just do it, and figure it out later, hahaha.

You shouldn't, and many demanding it are saying "bring me solutions not problems" to say "stfu and stop complaining" more politely. Let them faceplant.

No. I hate this mindset so much. People can protest without having a solution. If you do not want to iterate on or reconsider the status quo because someone "also doesn't have a better solution hurrdurr" you've mentally never left kindergarten.

No, even if something is the lesser of multiple evils, it still isn't immune to criticism, it just means there's more reason it must be "tolerated".

I try to do is build it with them and see what flaws we as a team encounter. That way it is us finding problems and solutions instead of me sitting in the back screaming complaints.